The invention relates to a computer system in which a population of computers has access to multiple applications. The computers may be personal computers (PC's) or, for example, integrated circuit cards (“IC cards”), also known as “smart cards”. The applications may be programs available from a variety of sources, including computer tape or disc, and, in particular, remote computers with which a serial link, typically by telephone, is established.
In the PC environment, it is customary to distribute applications on floppy discs or CD ROMS and to retain them on a local hard disc for operation. In many ways, this is inconvenient, demanding high capacity local storage media and presenting difficulties with updates. In the field of smart cards, the problem of local application storage is much more acute, because storage capacity in the integrated circuit is relatively very limited. A solution in both cases is to make available applications held remotely and download them via a remote link. Internet and intranet systems are ideal vehicles for this, and it is possible to run PC's from Internet application modules (or “applets” as they are called) for immediate running and then to discard them. The applets require no local long-term storage capacity. An example of such a system is JAVA.
Several difficulties are associated with downloaded applications. One is hardware compatibility. Different computers have different microprocessors and different operating systems. It has been customary to re-write applications to cater for different computers, but this is cost-effective only for large, widely used, and static applications. It is not practicable for applets. A second problem is control of the applets. Without control, it would be possible for applets to make direct hardware calls to take control of local storage or communication devices. This could be mischievous at best and severely damaging or criminal at worst.
JAVA meets these two difficulties by ensuring that the applets are written in a common high-level interpreted language and that a local interpreter processes the applet instructions. Thus, all applets are written in the same language, and the interpreter constitutes both a hardware and a control buffer. Similarly, and for the same reasons, proposals have been made for on-board interpreters in smart cards to run downloaded high-level language applications.
IC cards are becoming increasingly used for many different purposes in the world today. An IC card typically is the size of a conventional credit card which contains a computer chip including a microprocessor, read-only-memory (ROM), electrically erasable programmable read-only-memory (EEPROM), an Input/Output (I/O) mechanism, and other circuitry to support the microprocessor in its operations. An IC card may contain a single application or may contain multiple independent applications in its memory. MULTOS™ is a multiple application operating system which runs on IC cards, among other platforms, and allows multiple applications to be executed on the card itself. This allows a card user to run many programs stored in the card (for example, credit/debit, electronic money/purse, and/or loyalty applications), irrespective of the type of terminal (i.e., ATM, telephone, and/or POS) in which the card is inserted for use.
A conventional single application IC card, such as a telephone card or an electronic cash card, is loaded with a single application at its personalization stage when it is manufactured and before it is given to a card user. That application, however, cannot be modified or changed after the card is issued, even if the modification is desired by the card user or card issuer. Moreover, if a card user wanted a variety of application functions to be performed by IC cards issued to him or her, such as both an electronic purse and a credit/debit function, the card user would be required to carry multiple physical cards on his or her person, which would be quite cumbersome and inconvenient. If an application developer or card user desired two different applications to interact or exchange data with each other, such as a purse application interacting with a frequent flyer loyalty application, the card user would be forced to swap multiple cards in and out of the card-receiving terminal, making the transaction difficult, lengthy, and inconvenient.
Therefore, it is beneficial to store multiple applications on the same IC card. For example, a card user may have both a purse application and a credit/debit application on the same card, so that the user could select which type of payment (by electronic cash or credit card) to use to make a purchase. Multiple applications could be provided to an IC card if sufficient memory exists and an operating system capable of supporting multiple applications is present on the card. Although multiple applications could be preselected and placed in the memory of the card during its production stage, it would also be beneficial to have the ability to load and delete applications for the card post-production as needed.
The increased flexibility and power of storing multiple applications on a single card create new challenges to be overcome concerning the application loading process, in which information (including application code and associated data) is exchanged between the application provider and the individual card. The IC card only has a finite amount of memory on the card for storing applications. Applications and their associated data can vary drastically in size, depending upon the application. When multiple applications are stored on a card, and a series of application additions and deletions have occurred, memory fragmentation becomes an issue, where memory which is free cannot be used because of size limitations.
Additionally, an IC card has limited space in its input buffer, which can be separate or combined with an output buffer, i.e., an Input/Output (I/O) buffer. It may not be possible to fit the entire application and its associated data into an I/O buffer of an IC card at one time. In order to achieve the flexibility of selectively loading and deleting applications on an IC card, the problems of limited I/O buffer space and fragmentation must be addressed.
Accordingly, it is an object of this invention to provide a system and method that allows for flexible loading of an application and its associated data onto an IC card by segmenting the application and associated data into selected segments in order to limit the size of the data packets being transmitted at one time, and to reduce fragmentation in the memory of the IC card.
According to the invention, a computer system comprises a population of computers; tamper-resistant modules each associated respectively with one of said computers; a plurality of computer applications; provider means for holding the computer applications; and means for coupling the provider means to the computers for downloading the computer applications to the computers.
The computers may be PC's, in which case the tamper-resistant modules may be smart cards read by readers attached to the computers or, for example, dongles, PC cards, or PCMCIA cards connected to the computers.
In a preferred embodiment of the invention, the computers are embodied in integrated circuits which are themselves the tamper-resistant modules. Typically, the integrated circuits are mounted in smart cards.